1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to a projection-type illuminating unit and a display apparatus including the same, and more particularly, to an illuminating unit including a configuration for improving the efficiency of light transmitted to a display element and a display apparatus including the same.
2. Description of the Related Art
A display apparatus includes a display panel such as a liquid crystal display (LCD) or a plasma display panel (PDP) to process and display an image thereon. An example of a display apparatus which includes a large screen and realizes high quality image is a projection-type display apparatus, which projects an image displayed on a display panel to a large screen by various lens configurations.
The projection-type display apparatus transmits light from a light source, such as a lamp, to a display panel to thereby form an image on the display panel. However, as the lamp has a short life span and generates much heat, a light emitting diode (LED) has been increasingly used as the light source instead. The LED has a longer life span and generates less heat while providing excellent color realization and displaying a clearer image.
To display an image on the display panel, however, a light emission area should be larger than an effective area of the panel which displays an image. If the light emission area of the panel is smaller than the effective area, light is not sufficiently supplied to an edge of the image and thus the edge becomes dark or is not displayed. If the light emission area of the panel is much larger than the effective area, the light amount supplied to an area outside of the effective area, i.e., not used for displaying the image, increases. This leads to a decrease in light efficiency due to increased light loss.
The light emission area of the display panel relies on various lens configurations provided between the light source and the display panel. Thus, an arrangement of the lens configurations in consideration of the display status of the image and light efficiency is an important parameter for a design of a display apparatus.